Massive empyema caused by Mycoplasma pneumoniae in an adult: A case report

BACKGROUND: Mycoplasma pneumoniae is responsible for more than 20% of community acquired pneumonia cases, and capable of causing upper respiratory illness as well. Complications of M.pneumoniae infections include CNS involvement but other as pericarditis were also reported. The lack of feasible culture methods and under appreciation of the pathogens ability to cause invasive disease leads to reduced number of diagnosed M.pneumoniae related complications. In contrast to many other respiratory pathogens causing pneumonia, M. pneumoniae related severe pleural complications were almost never reported. CASE PRESENTATION: We report a previously healthy 57 years old woman presented with indolent massive right pleural effusion, leukocytosis and elevated ESR. Extensive microbiological evaluation didn't reveal any pathogen in the pus even before antibiotic treatment was started. Surprisingly, M.pneumoniae DNA was detected in the pus from the empyema using PCR designed to detect M.pneumoniae. A serological assay (Serodia-Myco II) using convalescent serum was indeterminate with a titer of 1:80. The patient responded well to a treatment that included right thoracotomy with pleural decortication and a combination of antibiotics and anti-inflammatory medications. CONCLUSION: M.pneumoniae related empyema was never reported before in adult patients and was reported in only a few pediatric patients. In our patient there was no evidence to any common pathogens even before initiating antibiotic treatment. The only pathogen detected was M.pneumoniae. In this patient, serology was not helpful in establishing the diagnosis of M.pneumoniae related diseases, as was suggested before for older patients. We suggest that M.pneumoniae related empyema is probably under-diagnosed complication due to insensitivity of serology in older patients and under use of other diagnosis methods

Retrospective survey for sialidase activity in Mycoplasma pneumoniae isolates from cases of community-acquired pneumonia

<p>Abstract</p> <p>Background</p> <p>Sialidase is a well-known virulence factor of other respiratory pathogens, but was only recently documented to occur in some species of <it>Mycoplasma</it>. The sialidase activity expressed can vary quantitatively among strains within a species of mycoplasma, from undetectable to amounts that correlate positively with strain virulence. Very few isolates of <it>Mycoplasma pneumoniae </it>had ever been examined for sialidase activity, so it was unknown whether sialidase may contribute to diseases involving this species.</p> <p>Findings</p> <p>No sialidase activity was detected by spectrofluorometric assay of 15 laboratory strains and 91 clinical isolates of <it>M. pneumoniae </it>banked over many years from patients having radiologically-confirmed, uncomplicated community-acquired pneumonia.</p> <p>Conclusions</p> <p>The annotated genome of strain M129 (GenBank <ext-link ext-link-id="NC_000912" ext-link-type="gen">NC_000912</ext-link>, <ext-link ext-link-id="ATCC29342" ext-link-type="gen">ATCC 29342</ext-link>), also isolated from a patient with pneumonia, accurately represents the absence of sialidase genes from strains of <it>M. pneumoniae </it>typically associated with uncomplicated community-acquired pneumonia. A possible involvement of sialidase in neurologic or other extra-respiratory manifestations of <it>M. pneumoniae </it>mycoplasmosis remains to be investigated.</p

CD39 abrogates platelet-derived factors induced IL-1β expression in the human placenta

Tissue insults in response to inflammation, hypoxia and ischemia are accompanied by the release of ATP into the extracellular space. There, ATP modulates several pathological processes, including chemotaxis, inflammasome induction and platelet activation. ATP hydrolysis is significantly enhanced in human pregnancy, suggesting that increased conversion of extracellular ATP is an important anti-inflammatory process in preventing exaggerated inflammation, platelet activation and hemostasis in gestation. Extracellular ATP is converted into AMP, and subsequently into adenosine by the two major nucleotide-metabolizing enzymes CD39 and CD73. Here, we aimed to elucidate developmental changes of placental CD39 and CD73 over gestation, compared their expression in placental tissue from patients with preeclampsia and healthy controls, and analyzed their regulation in response to platelet-derived factors and different oxygen conditions in placental explants as well as the trophoblast cell line BeWo. Linear regression analysis showed a significant increase in placental CD39 expression, while at the same time CD73 levels declined at term of pregnancy. Neither maternal smoking during first trimester, fetal sex, maternal age, nor maternal BMI revealed any effects on placental CD39 and CD73 expression. Immunohistochemistry detected both, CD39 and CD73, predominantly in the syncytiotrophoblast layer. Placental CD39 and CD73 expression were significantly increased in pregnancies complicated with preeclampsia, when compared to controls. Cultivation of placental explants under different oxygen conditions had no effect on the ectonucleotidases, whereas presence of platelet releasate from pregnant women led to deregulated CD39 expression. Overexpression of recombinant human CD39 in BeWo cells decreased extracellular ATP levels after culture in presence of platelet-derived factors. Moreover, platelet-derived factors-induced upregulation of the pro-inflammatory cytokine, interleukin-1β, was abolished by CD39 overexpression. Our study shows that placental CD39 is upregulated in preeclampsia, suggesting an increasing demand for extracellular ATP hydrolysis at the utero-placental interface. Increased placental CD39 in response to platelet-derived factors may lead to enhanced conversion of extracellular ATP levels, which in turn could represent an important anti-coagulant defense mechanism of the placenta

Identification of an N-terminal 27 kDa fragment of Mycoplasma pneumoniae P116 protein as specific immunogen in M. pneumoniae infections

<p>Abstract</p> <p>Background</p> <p><it>Mycoplasma pneumoniae </it>is an important cause of respiratory tract infection and is increasingly being associated with other diseases such as asthma and extra-pulmonary complications. Considerable cross-reactivity is known to exist between the whole cell antigens used in the commercial serological testing assays. Identification of specific antigens is important to eliminate the risk of cross-reactions among different related organisms. Adherence of <it>M. pneumoniae </it>to human epithelial cells is mediated through a well defined apical organelle to which a number of proteins such as P1, P30, P116 and HMW1-3 have been localized, and are being investigated for adhesion, gliding and immunodiagnostic purposes.</p> <p>Methods</p> <p>A 609 bp fragment P116_(N-27),corresponding to the N-terminal region of <it>M. pneumoniae </it>P116 gene was cloned and expressed. A C-terminal fragment P1_(C-40),of P1 protein of <it>M. pneumoniae </it>was also expressed. Three IgM ELISA assays based on P116_(N-27),P1_(C-40)and (P116 _(N-27)+ P1_(C-40)) proteins were optimized and a detailed analysis comparing the reactivity of these proteins with a commercial kit was carried out. Comparative statistical analysis of these assays was performed with the SPSS version 15.0.</p> <p>Results</p> <p>The expressed P116_(N-27)protein was well recognized by the patient sera and was immunogenic in rabbit. P1_(C-40)of <it>M. pneumoniae </it>was also immunogenic in rabbit. In comparison to the reference kit, which is reported to be 100% sensitive and 75% specific, ELISA assay based on purified P116_(N-27),P1_(C-40)and (P116_(N-27)+ P1_(C-40)) proteins showed 90.3%, 87.1% and 96.8% sensitivity and 87.0%, 87.1% and 90.3% specificity respectively. The p value for all the three assays was found to be < 0.001, and there was a good correlation and association between them.</p> <p>Conclusion</p> <p>This study shows that an N-terminal fragment of P116 protein holds a promise for serodiagnosis of <it>M. pneumoniae </it>infection. The IgM ELISA assays based on the recombinant proteins seem to be suitable for the use in serodiagnosis of acute <it>M. pneumoniae </it>infections. The use of short recombinant fragments of P116 and P1 proteins as specific antigens may eliminate the risk of cross-reactions and help to develop a specific and sensitive immunodiagnostic assay for <it>M. pneumoniae </it>detection.</p

Gene Expression Profiling via Multigene Concatemers

We established a novel method, Gene Expression Profiling via Multigene Concatemers (MgC-GEP), to study multigene expression patterns simultaneously. This method consists of the following steps: (1) cDNA was obtained using specific reverse primers containing an adaptor. (2) During the initial 1–3 cycles of polymerase chain reaction (PCR), the products containing universal adaptors with digestion sites at both termini were amplified using specific forward and reverse primers containing the adaptors. (3) In the subsequent 4–28 cycles, the universal adaptors were used as primers to yield products. (4) The products were digested and ligated to produce concatemers. (5) The concatemers were cloned into the vector and sequenced. Then, the occurrence of each gene tag was determined. To validate MgC-GEP, we analyzed 20 genes in Saccharomyces cerevisiae induced by weak acid using MgC-GEP combined with real-time reverse transcription (RT)-PCR. Compared with the results of real-time RT-PCR and the previous reports of microarray analysis, MgC-GEP can precisely determine the transcript levels of multigenes simultaneously. Importantly, MgC-GEP is a cost effective strategy that can be widely used in most laboratories without specific equipment. MgC-GEP is a potentially powerful tool for multigene expression profiling, particularly for moderate-throughput analysis

The Impact of Different Antibiotic Regimens on the Emergence of Antimicrobial-Resistant Bacteria

Backgroud: The emergence and ongoing spread of antimicrobial-resistant bacteria is a major public health threat. Infections caused by antimicrobial-resistant bacteria are associated with substantially higher rates of morbidity and mortality compared to infections caused by antimicrobial-susceptible bacteria. The emergence and spread of these bacteria is complex and requires incorporating numerous interrelated factors which clinical studies cannot adequately address. Methods/Principal Findings: A model is created which incorporates several key factors contributing to the emergence and spread of resistant bacteria including the effects of the immune system, acquisition of resistance genes and antimicrobial exposure. The model identifies key strategies which would limit the emergence of antimicrobial-resistant bacterial strains. Specifically, the simulations show that early initiation of antimicrobial therapy and combination therapy with two antibiotics prevents the emergence of resistant bacteria, whereas shorter courses of therapy and sequential administration of antibiotics promote the emergence of resistant strains. Conclusions/Significance: The principal findings suggest that (i) shorter lengths of antibiotic therapy and early interruption of antibiotic therapy provide an advantage for the resistant strains, (ii) combination therapy with two antibiotics prevents the emergence of resistance strains in contrast to sequential antibiotic therapy, and (iii) early initiation of antibiotics is among the most important factors preventing the emergence of resistant strains. These findings provide new insights into strategies aimed at optimizing the administration of antimicrobials for the treatment of infections and the prevention of the emergence of antimicrobial resistance

Bacterial Community Profiling of Milk Samples as a Means to Understand Culture-Negative Bovine Clinical Mastitis

Inflammation and infection of bovine mammary glands, commonly known as mastitis, imposes significant losses each year in the dairy industry worldwide. While several different bacterial species have been identified as causative agents of mastitis, many clinical mastitis cases remain culture negative, even after enrichment for bacterial growth. To understand the basis for this increasingly common phenomenon, the composition of bacterial communities from milk samples was analyzed using culture independent pyrosequencing of amplicons of 16S ribosomal RNA genes (16S rDNA). Comparisons were made of the microbial community composition of culture negative milk samples from mastitic quarters with that of non-mastitic quarters from the same animals. Genomic DNA from culture-negative clinical and healthy quarter sample pairs was isolated, and amplicon libraries were prepared using indexed primers specific to the V1–V2 region of bacterial 16S rRNA genes and sequenced using the Roche 454 GS FLX with titanium chemistry. Evaluation of the taxonomic composition of these samples revealed significant differences in the microbiota in milk from mastitic and healthy quarters. Statistical analysis identified seven bacterial genera that may be mainly responsible for the observed microbial community differences between mastitic and healthy quarters. Collectively, these results provide evidence that cases of culture negative mastitis can be associated with bacterial species that may be present below culture detection thresholds used here. The application of culture-independent bacterial community profiling represents a powerful approach to understand long-standing questions in animal health and disease